A quantitative study of the influence of non-expansive sulfoaluminate cement on the corrosion of steel reinforcement

摘要

The corrosion resistance of steel reinforced mortar specimens made from non-expansive sulfoaluminate cement was investigated using Ordinary Portland Cement (OPC) specimens as reference. The specimens were prepared and exposed in three different environments, namely, continuous exposure in tap water, continuous exposure in 3.5 percent NaCl solution and intermittent exposure in 3.5 percent NaCl solution. The steel weight loss (WL) and the half cell potential (HCP) were measured vs. exposure time, up to the age of 12 months. Pore solution extraction and analysis and porosity determination were also performed. In continuous exposure in tap water, sulfoaluminate cement provided adequate protection against corrosion. In continuous exposure in 3.5 percent NaCl solution, a higher corrosion was observed. In the ease of intermittent exposure in 3.5 percent NaCl solution, the simultaneous action of free chlorides and oxygen, as well as the low pH of the pore solution, resulted in the depassivation of steel reinforcement and led to severe corrosion effect.